How to theme a menu block in Drupal?

Question

This should really be a basic question but I simply don't get it after hours of searching. The question is, how do I theme menu blocks in Drupal 7?

I've created three different blocks all based on the main menu. Now I want to:

1. create unique HTML for all three blocks, that means modifing the surrounding wrapper and the <ul> and <li> that builds the menu. I wanna set special classes and remove all of the Drupal-added stuff

2. attach different classes to the different levels within each block. One of blocks will show two levels of the menu, i.e. it will display a submenu. I want to set a special class on the for the submenu...

This seems impossible... :(

Thank you in advance for the help!!!!

Answer 1

Theming is a tricky beast that often varies a lot depending what you need to do. Even with your very detailed description I can still say "it depends", but here are a couple steps that may help you get pointed in the right direction.

Step 1: Use a block tpl.php as suggested by Caffeine Addict. If you're not sure what to name the .tpl.php, I recommend the Theme Developer module. It's buggy, but you can use it to select an particular element and have it tell you suggestions for naming of .tpl.php files.

Step 2: Use a theme / preprocess function in template.php to modify the pre-defined variables and markup. Be sure to check on the theme_menu_tree & template_preprocess_menu_tree functions on api.drupal.org for starting points. If you're using the devel module, use dpm($variables); in each of those to see what you have to work with from the start.

I hope that helps! I agree with Caffeine Addict when he says that superfish might be an alternative. You should also probably check out the menu block module for breaking out conditional sub-sections into their own blocks.